videohelp.com has a tutorial that shows you one way of doing it with free software here: http://www.videohelp.com/forum/archive/t209980.html
It's a bit technical, but it is free, the way it does it actually involves creating a subtitle file with the date and time stamp in it (which is then added to the .avi file with virtualdub mod),
so as you're planning on producing a DVD of the footage you could just skip the last step in the tutorial and add the subtitle in your DVD Authoring app' and you'd be able to switch the time stamp on or off while you watch.
__________________ P4 1GB Ram 50+160GB, Win XP, Premiere 6, Encore+Photoshop, Lite-on 4x dvd rw.
Sony TRV-250, Panasonic NVGS-75, Canon MV600i |